• Journal of Multimedia Information System
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• 제4권1호
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• pp.19-26
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• 2017

The compression of video for both full HD and UHD requires the inclusion of extra vertical lines to every video frame, named as the DTV essential hidden area (DEHA), for the effective functioning of the MPEG-2/4/H encoder, stream, and decoder. However, while the encoding/decoding process is dependent on the DEHA, the DEHA is conventionally viewed as a redundancy in terms of channel utilization or storage efficiency. This paper proposes a block mode DEHA method to more effectively utilize the DEHA. Partitioning video block images and then evenly filling the representative DEHA macroblocks with the average DC coefficient of the active video macroblock can minimize the amount of DEHA data entering the compressed video stream. Theoretically, this process results in smaller DEHA data entering the video stream. Experimental testing of the proposed block mode DEHA method revealed a slight improvement in the quality of the active video. Outside of this technological improvement to video quality, the attractiveness of the proposed DEHA method is also heightened by the ease that it can be implemented with existing video encoders.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.445-449
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• 1988

Digital processing of measured data offers a powerful means to improve the resolution and quality of ultrasonic imaging. The present research demonstrates that filtering typical B-scan images using Wiener filter enhances lateral resolutions by more than 50 percent. The filter is operated using the measured signal amplitude across the transmitter beam and the beam with. It is optimized for low noise and high resolution By an empirical approach. This bethod for lateral filtering produces a very useful result for the line images with high interference by neighboring lines.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.449-451
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• 2000

Arcing fault on overhead lines can be detected by amplitude of the arc voltage using numerical algorithm. In the case of transient fault, the arc voltage has any high value. In the case of permanent fault, the arc voltage is near zero. Thus, fault distance estimation should be performed by digital distance relay algorithm[3]. The purpose of this study is to build a structure for modeling of arcing fault detection and fault distance estimation algorithm using Matlab programming. Additionally, this algorithm has been designed in Graphical User Interface(GHI). So, this method using GUI interface of Matlab can reduce the number of simulation steps in modeling the distance relay.

• 시큐리티연구
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• 제5호
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• pp.211-241
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• 2002

Koreans are the most avid Internet surfers in the world according to Nielson/NetRatings(Reuters, August 2001) and most Internet connections are made through high-speed connections like Digital Subscriber Lines (DSLs). The result of such internet fervor is a nation that is fertile in both hackers and software companies(over 200 in the field of network security alone). However, by-product of Internet activity is cyber crime and the need to protect innocent users from the dangers of cyber criminals and cyber-terrorists be they are individuals or organized groups. Hence the Cyber Terror Response Team (CTRT) was organized in late 2000 with the mandate to fulfill that role. In these contexts, this study analyzes the actual conditions of cyber terror and suggests the countermeasures against cyber terror in Korea.

• 대한전자공학회논문지
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• 제25권8호
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• pp.859-866
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• 1988

A high speed frame synchronization system has been realized which generates the frame sync clock from 565Mb/s data stream (the DS-5 digital multiplex hierarchy signal). The design of a frame pattern detector using a parallel detection method brings into low speed operation and resolves the problems due to the high speed operation. The frame synchronization algorithm recommended by CCITT is also realized by designing a sync mode controller. Appropriate design procedures are considered for an efficient hardware design and minimized connection lines. The CAD simulation as well as experiment show that the performance of the newly designed frame synchronization system satisfies the relevant requirements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.305-309
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• 1989

This paper presents a simple method to compensate reactive/harmonic current components in power lines, with voltage type current controlled converter. The method proposed differs from conventional methods in that it does not rely on explict evaluation of active power. Instead, the closed-loop control of the do link voltage of the compensator plays a major role in adjusting the compensation current. It is shown that the system can be modelled as a simple linear system, which facilitates th analytical approach to the system characteristics. The dynamic performances are examined through the digital simulation and some aspects on the controller design are discussed. Experimental results showed good agreement with the anticipate performance

• 한국전자파학회지:전자파기술
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• 제14권1호
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• pp.35-42
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• 2003

Differential signaling has become a popular choice for high-speed interconnection schemes on Printed Circuit Boards (PCBs), offering superior immunity to external noise. However, conventional differential transmission lines on PCBs have problems, such as crosstalk and radiated emission. To overcome these, we propose a Twisted Differential Line (TDL) structure on a multi-layer PCB. Its improved immunity to crosstalk noise and the reduced radiated emission has been successfully demonstrated by measurement. The proposed structure is proven to transmit 3 Gbps digital signals with a clear eye-pattern. Furthermore, it is subject to much less crosstalk noise and achieves a 13 dB suppression of radiated emission. Index Terms - Twisted Differential Line, Differential Signaling, Crosstalk, Radiated Emission, Transmission Line, Twisted Pair

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.795-803
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• 2015

Autoreclosure provides a means of improving power transmitting ability and system stability. Conventional reclosure adopts the fixed dead time interval strategy, where the reclosure is activated after a time delay to restore the system to normal as quickly as possible without regard to the system conditions. However, these simple techniques cannot provide optimal operating performance. This paper presents an adaptive autoreclosure algorithm including variable dead time, optimal reclosure, phase-by-phase reclosure and emergency extended equal-area criterion (EEEAC) algorithm in order to improve system stability. The reclosure algorithm performs the operations that are attuned to the power system conditions. The proposed adaptive reclosure algorithm is verified and tested using ATP/EMTP MODELS, and the simulation results show that the system oscillations are reduced and the transient stability is enhanced by employing the proposed adaptive reclosure algorithm.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.675-676
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• 2013

본 논문에서는 TDBM과 CMTEDD를 사용하여 다중출력조합디지털논리시스템 설계방법의 한가지를 제안하였다. 또한, CBDD와 CMTEDD를 기반으로 최종 조합디지털논리시스템 구성을 멀티플렉서를 사용하여 구현하였다. 제안한 방법은 기존의 방법에 비해 모듈사이의 내부결선을 효과적으로 줄일 수 있으며 입력변수의 쌍과 출력함수의 쌍에 의해 게이트 수를 줄일 수 있는 장점이 있다.

• 대한전기학회논문지:전력기술부문A
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• 제52권10호
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• pp.593-601
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• 2003

Distance realy is tripped by the line impedance calculated at the relay point. Accordingly the accurate operation depends on the precise calculation of line impedance. Impedance can be accurately calculated in case of overhead line. However, in case of power cables or combined transmission lines, impedance can not be accurately calculated because cable systems have the sheath, grounding resistance, and sheath voltage limiters(SVLs). There are also several grounding systems in cable systems. Therefore, if there is a fault in cable systems, these terms will severely be caused much error to calculation of impedance. Accordingly the proper compensation should be developed for the correct operation of the distance relay. This paper presents the distance calculating algorithm in combined transmission line with power cable using wavelet transform. In order to achieve such purpose, judgement method to discriminate the fault section in both sections was proposed using D1 coefficient summation in db4. And also, error compensation value was proposed for correct calculation of impedance in power cables section.